Example 71 Bgp Open Message

Frame Status Source Address Dest.

Address Size Rel.

Time Delta Time Abs.

Time

Summary

8 [10.50.4.1] [10.50.4.2] 99 0:00:37.326 0.003.216

04/28/2002

03:14:50 PM

BGP: type = Open

DLC: -----

DLC Header -----

DLC:

DLC: Frame 8 arrived at 15:14:50.2341; frame size

is 99 (0063

hex) bytes.

DLC: Destination = Station 000427228197

DLC: Source = Station 0004272281D8

DLC: Ethertype = 0800 (IP)

DLC:

IP: -----IP Header-----

IP:

IP: Version = 4, header length = 20 bytes

IP: Type of service = C0

IP: 110 = internetwork control

IP: ...0 = normal delay

IP: 0... = normal throughput

IP: 0.. = normal reliability

IP: 0. = ECT bit - transport protocol will

ignore the o

CE bit

IP: 0 = CE bit - no congestion

IP: Total length = 85 bytes

IP: Identification = 2

IP: Flags = 0X

IP: .0 = might fragment

IP: ..0 = last fragment IP: Fragment offset

= 0 bytes

IP: Time to live = 1 seconds/hops

IP: Protocol = 6 (TCP)

IP: Header checksum = 9C7B (correct) IP: Source address = [10.50.4.1] IP: Destination address = [10.50.4.2] IP: No options IP:

TCP:

TCP: Source port = 11002

TCP: Destination port = 179 (BGP)

TCP: Sequence number = 3817488861

TCP: Next expected Seq number= 3817488906

TCP: Acknowledgment number = 3816595146

TCP: Data offset = 20 bytes

TCP: Window = 16384

TCP: Checksum = 97C3 (correct)

TCP: No TCP options labs include all of the tech

TCP:

BGP: Hold Time = 180 Second(s)

BGP:

BGP Identifier = C0A80501, [192.168.5.1] BGP:

BGP: Optional Parameters Length = 16

BGP: Unknown Option Data

BGP:

ADDR HEX

ASCII 0000:

00 04 27 22 81 97 00 04 27 22 81 d8 08 00 45 c0 | .."

0010: 00 55 00 02 00 00 01 06 9c 7b 0a 32 04 01 0a 32

0020: 04 02 2a fa 00 b3 e3 8a 41 dd e3 7c 9e ca 50 18

0030: 40 00 97 c3 00 00 ff ff ff ff ff ff ff ff ff ff

0040: ff ff ff ff ff ff 00 2d 01 04 00 01 00 b4 c0 a8

0050: 05 01 10 02 06 01 04 00 01 00 01 02 02 80 00 02

BGP Capabilities Advertisement

Starting with BGP-4; BG P pe er cad^billties can be negotiated durmg sesy i on BGP init i plizteior, using the Optional Cataeilit ies pacametier, which i s cantained in the OPEN messagei BGb tapab ilitie s negotiation is deshribed s RFC 228342. This element wa s ooded into BGP so that new features could be added into the BGP specification without requiring upgrades to newer versions of the protocol.

Using capabilities advertisement, peers can exchange capabilities and negotiate a session using the most agreed-upon features. If one of the peers does not support an optional parameter, it sends the advertiser a NOTIFICATION message with the error "Unsupported Optional Parameter." After receiving the NOTIFICATION message, the advertising peer resends the message without the unsupported parameter and so on, until both peers agree on a set of parameters.Table 7-4 describes the IANA-defined BGP capabilities codes.

Table 7-4. BGP Capabilities Codes

Capabilities Code

Description

0

Reserved

1

Multiprotocol extensions for BGP-4

C

ROUTE-REFRESH capability for BGP-4

3

Cooperati ve route filtering capability

4

Multiple routes to a destination capability

5-63

Unassigned

64

Graceful restart capability

65

Support for 4-octet AS number capability

66

Support for dynamic capability

128-255

Vendor specific

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